The present invention pertains to a fire-resistant polyamide composition that shows improved molding fluidity and superior tensile modulus and Izod impact strength.
Polyamide resins are used in a variety of fields, such as electrical and electronic parts, etc., due to their superior mechanical properties, electrical properties, chemical resistance, etc. However, since superior fire resistance is needed in certain fields, research is being performed in order to obtain polyamide resins with superior fire resistance when compared to conventional resins. Moreover, methods whereby a variety of flame retarders, such as halogen compounds, phosphorous compounds, etc., are mixed in order to obtain fire-resistant polyamide resin compositions have been used in the past. In particular, polyamide resin compositions in which melamine cyanurate has been added as the flame retarder are known to provide molded articles that show no generation of toxic components with pyrolysis [Japanese Kokai Patent No. Sho 53(1978)-31759].
Moreover, research is also being performed on improvement of molding fluidity of fire-resistant polyamide resin compositions in order to obtain molded articles of complex shapes, as well as molded articles having thin walls. Although polyamide resins with a low molecular weight, i.e., a low viscosity, can be used to improve molding fluidity, the superior mechanical properties of the polyamide resin itself cannot be retained when polyamide resins with a low molecular weight are used. Therefore, fire-resistant polyamide resin compositions to which bisamides and stearic acid stearates have been added are being developed in order to retain mechanical properties while improving fluidity [Japanese Patents No. Sho 56(1981)-21065 and No. Hei 1(1989)-38820]. Nevertheless, molding conditions are restrictive and it is difficult to obtain good molded articles under a wide range of molding conditions with these fire-resistant polyamide resin compositions containing bisamides and stearic acid stearates. Consequently, there is a demand for further improvement of molding fluidity of fire-resistant polyamide resin compositions.
In light of the aforementioned circumstances, the purpose of this invention is to present a fire-resistant polyamide resin composition with improved molding fluidity. As a result, molded articles of a complex shapes and thin molded articles having superior tensile modulus and Izod impact strength can be obtained under a wide range of molding conditions.